Novel Observations in Charmonium Decays

Four novel observations in charmonium decays are presented in this talk. The first observation is $\psi(3686)\rightarrow 3\phi$ decay, which sheds light on the rare decay process of the $\psi(3686)$ resonance into three $\phi$ mesons, providing valuable insights into the dynamics of charmonium decays. No significant structure is observed in the $\phi\phi$ invariant mass. The second one is the search for $\eta_c(2S)\rightarrow\pi^+\pi^-\eta_c$ and $\eta_c(2S)\rightarrow\pi^+\pi^-K^0_SK^{\pm}\pi^{\pm}$ decays. This study aims to explore the decay properties of the $\eta_c(2S)$ meson, offering new perspectives on its decay modes and contributing to our understanding of charmonium states. The third one is the $\psi(3686)\rightarrow \Omega^-K^+\bar{Xi}^0$ decay. Possible baryon excited states are searched for in this decay, but no evident intermediate state is observed with the current sample size. The fourth observation is the decay of $\chi_{cJ} (J=0,1,2)\rightarrow 3(K^+K^-)$.